NASA has selected PRIMA, a far-infrared space telescope, as the first mission of its new Probe Explorers class — the agency's first mission of its kind in more than a decade. The project is capped at $1.2 billion excluding launch and other non-project costs, with a launch targeted for 2033 on a planned five-year mission.
PRIMA stands for PRobe far-Infrared Mission for Astrophysics. Its job is to survey the universe in a wavelength range that sits between existing infrared observatories and radio telescopes — cold material that has largely been invisible to prior instruments.
That coldness is the point. Far-infrared emission comes from cool dust and gas: the disks around young stars where planets form, and the dust in galaxies that absorbs starlight and re-emits it. A large share of the material from which worlds are built has so far been measurable only indirectly.
Among PRIMA's targets are planet-forming disks — which it will effectively weigh — and dusty galaxies. Another goal is the debris of neutron-star mergers, the events that forge and distribute heavy elements such as gold. The project is now moving into Phase B, the detailed design stage, with several Johns Hopkins researchers on the team.
The selection is also an argument about cost. Small and medium space telescopes are cheaper than flagship observatories and complement them. PRIMA will be less capable but far more focused — and the first of a class intended to let NASA answer new questions faster.
